Thread: Dust extractor and ventilation.

Originally Posted by tonzeyd

Might be a good idea to give Timbecon a call regarding that 3hp DC and check the amperage.

Yeah already sent an email asking what the amperage was and how much delivery would be, same to Machinery House.

Originally Posted by BobL

I'm pretty sure it will be a 15A machine.

The plate on the Hafco unit at Machinery House indicates it's only 10A so assumed the Sherwood would be the same. Will find out soon enough.

Also with these twin bag units, can you close off a side and run them with only one bag or would the volume moved be too much?

Originally Posted by Tigglez

Also with these twin bag units, can you close off a side and run them with only one bag or would the volume moved be too much?

Volume would be too much, severely compromising performance even when the filter is cleanish and the single filter bag will clog up quicker.
This is further demonstrated if folded pleated paper filters are use increasing air flow by a further ~10%

The plate on the Hafco unit at Machinery House indicates it's only 10A so assumed the Sherwood would be the same. Will find out soon enough.

They draw about 9A but they have very high start up currents (~60A) so when they are turned on they will often trigger circuit breakers that are already under some load which is a right PITA.

By way of a comparison, 3HP TS are not started under much load and have start up currents around 35A which most breakers on a 10A circuit will allow for provided it's only for a very short time period. However under load a TS can draw well over 10A which is why these usually have 15A plugs.

Another factor is that even though a 3HP DC draws <10A while running, they typically are on for some time so they constantly consume most of the current on a 10A circuit. Most 10A circuits use a 16A breaker so you have 7A left to play with. This is OK for about a 1HP machine but anything above that is likely to run into probs.

So even if they have 10A plug they are really worth putting on their own circuit.

Originally Posted by BobL

They draw about 9A but they have very high start up currents (~60A) so when they are turned on they will often trigger circuit breakers that are already under some load which is a right PITA.

If you are getting a new circuit installed, request that the sparky put a 'D' curve circuit breaker on the circuit.
Normal circuits are C curve breakers which will sometimes trip when there is already a load on the circuit, then motor start up current is added as Bob stated. A D curve breaker takes a bit longer to trip, allowing the motor time to run up to speed.

TC one is 15A, be interesting to see what MH say about theirs.

Doesn't matter too much, had a gas/electric oven replaced with an all gas one so am going to get that wiring extended to the shed and run the DC on it when I get another circuit installed.

Guess I should prob have the other circuit 15A should I ever get some bigger machinery.

Originally Posted by Tigglez

Guess I should prob have the other circuit 15A should I ever get some bigger machinery.

Yes you need at least 2 in a shed.

Is there some kind of plate or inset you can get to put over the hole I'll make in the wall for the 6" pvc so that it looks better instead of having to make something myself?

And if I put a plywood floor in the shed to run the 6" pvc under will some vents on the plywood be enough for subfloor ventilation or would it require cross ventilation from the subfloor shed wall?

Originally Posted by Tigglez

Is there some kind of plate or inset you can get to put over the hole I'll make in the wall for the 6" pvc so that it looks better instead of having to make something myself?

Not really, I have made these plates in a number of ways and they are very easy to make.

One way is to cut a suitable hole in a square piece of thin galv sheet metal or MDF that is say 250 x 250 mm and slide that over the duct and screw or glue that to the wall.
If you ducting is already in place you can make the plate in two halves and glue/screw these either side of the ducting.
To get a good seal around the duct/hole you can glue or silicone one of these into place.
Screen Shot 2018-04-26 at 5.21.30 pm.png
https://www.bunnings.com.au/holman-1...lange_p4750174
NB this is the 100 mm version - Bunnings don't sell these in 150 mm version you will need to go to a PVC ducting specialist store - they are not cheap (~$7) so I made my own.

And if I put a plywood floor in the shed to run the 6" pvc under will some vents on the plywood be enough for subfloor ventilation or would it require cross ventilation from the subfloor shed wall?

You'd need to make the support frame for the ply very strong and use 18 mm ply or it will bounce around under the weight and operation of machinery.
Yes you would need to vent it.
I have one underfloor duct to where my TS is located - best thing I ever did although it's fixed in concrete so I better not change my mind about its location.
It's just easier to come in OTT of machines with ducting - I'd hate to have to move machines around and lift teh floor to change my ducting.